Taking a Closer Look at Infertility
About one in six married couples in the United States is unable to conceive a child on their own. In roughly one-third of the cases, doctors diagnose so-called “male-factor infertility”--that is, the problem lies with the man. (The female partner is found to be infertile one-third of the time too; in all other cases, a combination of factors interferes with the baby-making process.)
For the last half-century, doctors have measured men’s ability to produce progeny using the same set of standards, which were established by the World Health Organization. A guy is generally considered fertile if his semen contains at least 20 million sperm cells per milliliter, and at least half of those sperm are motile, meaning that they are good swimmers, able to navigate the birth canal, giving them a chance to inseminate the egg. (Having a lot of normal-shaped sperm appears to be important too, though there has been less consensus on what percentage is optimal for insemination.)
But a study published last month in the New England Journal of Medicine suggests that it may be time to rethink these standards. Among other things, researcher David S. Guzick and his colleagues found that the long-standing yardstick of 20 million sperm per milliliter doesn’t accurately predict one’s ability to father a child.
Guzick, chairman of obstetrics and gynecology at the University of Rochester School of Medicine and Dentistry in New York, led a team of researchers from nine fertility clinics across the country. They analyzed semen samples from 765 males in infertile couples; in each of these pairs, doctors suspected male-factor infertility, since the woman had been evaluated and determined to be healthy and able. The University of Rochester group compared these samples with semen from 696 males who had either fathered a child within the prior two years or whose partner was pregnant.
The group found that the strongest indicator of male fertility was the appearance of the sperm; guys who had a large percentage of normal-shaped reproductive cells were the ones most likely to impregnate their partners. They also learned that the men most likely to become dads had semen with at least 48 million sperm per milliliter. On the other hand, the study identified men with semen samples containing fewer than 13.5 million sperm per milliliter as “subfertile.” In between, Guzick discovered what he calls a “gray zone,” in which a guy’s sperm count was less useful in predicting whether he was fertile. In fact, some men with fewer than 20 million sperm became fathers, while other men above the threshold did not. These men he identified as having “indeterminate fertility.”
Urologist Robert Brannigan, a fertility specialist at Northwestern University Memorial Hospital in Chicago, says Guzick’s findings could improve the way infertile couples are evaluated in this country. Although doctors who specialize in fertility treatment are well aware of the gray zone Guzick describes, many couples who can’t conceive are often first examined by a family doctor or internist. These generalists, like many gynecologists and urologists, aren’t necessarily fertility experts, and they may not be aware that the 20-million-sperm-count standard is somewhat arbitrary. Here’s how Guzick’s proposed new guidelines might come into play, says Brannigan. Say a couple in their late 30s have been trying without success to have a baby for a few months. They both are healthy and capable of conceiving a child, according to current standards; the guy’s sperm count is a shade over 20 million per milliliter. Typically, a family doctor might send this couple home and tell them to continue trying to conceive the natural way for a year.
A doctor using Guzick’s guidelines, however, might suspect the guy could use a little help. The doctor would then refer the couple to a fertility specialist, who could discuss how the various forms of assisted reproductive technology might increase their chances of having a child. The year saved could be critical, especially for older couples, since a woman’s fertility declines with age. For many patients, says Brannigan, “Time is of the essence.”
Brannigan is quick to add, however, that a man whose sperm count falls into the gray zone still needs a thorough examination, to be absolutely certain there are no hidden medical problems--some potentially serious--that may be impairing his fertility.
“There can be abnormalities present that won’t be detected by a semen analysis,” Brannigan says. He knows of two men from infertile couples who actually hadtesticular cancer.
Guzick thinks his new system could help ease a common problem among male partners in couples struggling to conceive: guilt. Men currently labeled as “abnormal” are often left feeling like they’re to blame for a couple’s inability to have a baby. “But those men might be completely fine,” says Guzick. By some estimates, there are more than 6 million infertile married couples in the United States; if male-factor infertility is detected one-third of the time, that could leave a whole lot of guys feeling a lot less blame.
Tracy Rankin, a program director at the National Institute of Child Health and Human Development, doesn’t think doctors and labs in the United States are likely to abandon existing standards and adopt Guzick’s guidelines any time soon. However, she says, the University of Rochester study does “point out the need to reexamine the guidelines used in clinics.”
Which sounds to me like a pretty good idea, especially if some variation on Guzick’s gray zone comes into widespread use. After all, sometimes a little ambiguity can clear a man’s mind.
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Massachusetts freelance writer Timothy Gower is at tgower@mediaone.net.
